Order of operations

The algebra order of operations is a conventional way to solve algebraic expressions.

In the USA it is often also used this acronym:

PEMDAS or "Please Excuse My Dear Aunt Sally"

which recalls

Parentheses , first ( ), then [ ], then { }

Exponential

Multiplication (from left to right)

Division (from left to right)

Addition (from left to right)

Subtraction (from left to right)

So to solve the following example you proceed the following way:

451. When the boy begins to understand that the visible
point is preceded by an invisible point, that the shortest dis-
tance between two points is conceived as a straight line before
it is ever drawn with the pencil on paper, he experiences a feeling
of pride, of satisfaction. And justly so, for the fountain of all
thought has been opened to him, the difference between the
ideal and the real, potentia et actu, has become clear to him;
henceforth the philosopher can reveal him nothing new, as a
geometrician he has discovered the basis of all thought.